Identify the protected alias affected by a proposed edit

internal/framework/validators/protected_terms.go

@@ -99,8 +99,23 @@ func validateIdentityPreservation(beforeByID, afterByID map[glossary.Identity][]
 	var selected string
 	found := false
 	for identity, beforeItems := range beforeByID {
-		if len(afterByID[identity]) < len(beforeItems) && len(beforeItems) > 0 {
-			if spelling := beforeItems[0].canonical; !found || spelling < selected {
+		afterItems := afterByID[identity]
+		if len(afterItems) >= len(beforeItems) {
+			continue
+		}
+		// Protect identity counts. Within an identity that lost a mention,
+		// use spelling counts to identify which alias was affected.
+		remaining := make(map[string]int)
+		for _, item := range afterItems {
+			remaining[item.canonical]++
+		}
+		for _, item := range beforeItems {
+			spelling := item.canonical
+			if remaining[spelling] > 0 {
+				remaining[spelling]--
+				continue
+			}
+			if !found || spelling < selected {
 				selected, found = spelling, true
 			}
 		}

internal/framework/validators/protected_terms_test.go

@@ -3,6 +3,7 @@ package validators
 import (
 	"reflect"
 	"sort"
+	"strings"
 	"testing"
 
 	domain "gitea.maximumdirect.net/eric/audita/v3/internal/core/glossary"
@@ -107,3 +108,28 @@ func TestProtectedNameRepetitionRequiresSurvivingIdentityAndSpokenWordScope(t *t
 		})
 	}
 }
+
+func TestProtectedNameFindingIdentifiesRemovedAlias(t *testing.T) {
+	req := Request{
+		ModuleKey:           "glossary",
+		IndependentEvidence: true,
+		ReplacementPolicy:   proposals.ReplacementPolicyReplaceAll,
+		WorkingTranscript: &schema.Transcript{Segments: []schema.Segment{
+			{ID: 1, Text: "Mira spoke to Captain Mira"},
+		}},
+		ProtectedTerms: domain.Vocabulary([]domain.Entry{{ID: "mira", Name: "Mira", Aliases: []string{"Captain Mira"}}}, nil),
+		CandidateProposal: []proposals.EnrichedCorrectionProposal{{
+			CorrectionProposal: proposals.CorrectionProposal{
+				TargetSegmentID: 1, OriginalText: "Captain Mira", CorrectedText: "the captain", Confidence: 0.9,
+			},
+		}},
+	}
+	result, err := ValidateProtectedTerms(req)
+	if err != nil || len(result.Decisions) != 1 {
+		t.Fatalf("result=%+v err=%v", result, err)
+	}
+	decision := result.Decisions[0]
+	if decision.Approved || decision.ReasonCode != ReasonProtectedGlossaryTerm || !strings.Contains(decision.Message, `"Captain Mira"`) {
+		t.Fatalf("finding did not identify the removed alias: %+v", decision)
+	}
+}